1. Field of the Invention
The present invention generally relates to a solar cell, and more particularly, to a back side contact solar cell.
2. Description of Related Art
Silicon-based solar cell is one of the solar cells generally used in the field. The principle of a silicon-based solar cell is to add dopants in a semiconductor material (silicon) with high purity, such that the semiconductor material presents different characteristics and forms p-type semiconductors and n-type semiconductors. After conjugating these two types of semiconductors, p-n conjunctions are formed. When the sunlight irradiates on a semiconductor with a p-n structure, the energy provided by photons may excite the electrons in the semiconductor and generate electron-hole pairs. A solar cell is constituted by disposing electrodes such that the holes move toward the direction of the electric field and the electrons move toward the opposite direction.
In general, with the thickness of the semiconductor material in a solar cell becomes less, the amount of incident light in the front surface and the amount of light absorbed in the back surface of the solar cell would decrease. Therefore, under the trend of developing thinner solar cells, how to increase the amount of light absorbed by a solar cell becomes one of the key points in the research and development.